In both cases (6, 7), your easiest path of installation is probably to just hook into EPEL repositories and install BackupPC (3.3.1) via yum. Certainly a lot easier than finding and installing dependencies manually.
I'm in a similar dilemma with regards to CentOS 7 upgrades, but I figure I have 5 more years to deal with it. Hopefully some kind soul will be maintaining 4.x in EPEL by then.
p.s. Thanks to Bernard Johnson for maintaining the current version.